Question

Consider the line L given by the point-slope equation y+7= 1/2(x−18).

The y-intercept of the line is located at (0, b)

What is the value of b?

Answer 1

• - 16

Explanation:

The y-intercept is the coordinate of y when x = 0.

Find the value of y:

• y + 7 = 1/2(0 - 18)
• y + 7 = 1/2( - 18)
• y + 7 = - 9
• y = - 9 - 7
• y = - 16

Answer 2

b = -16

Explanation:

To find the
`y`-intercept, rewrite the equation in the form
`y=mx+c` (where
`m` is the slope and
`c` is the
`y`-intercept).

`y + 7 = (1)/(2)(x - 18)`

multiply out the brackets:
`y + 7 = (1)/(2) x - 9`

Subtract 7 from each side:
`y = (1)/(2) x - 16`

Therefore, when x = 0, y = -16

So the value of b is -16